Investors expect a blue wave in next week's midterm election , as Democrats surge in polls and President Donald Trump 's approval rating remains low.

Public polling suggests Democrats are likely to take control of the House of Representatives, and analysts who parse what politics means for investors are in overdrive to tell their clients how to prepare for what Congress will look like after the Tuesday election.

Concern about the spending plans and priorities of a Democratic-controlled Congress permeates analyst reports reviewed by CNBC. But because Trump has another two years of his presidency, a divided government would likely create gridlock that would prevent congressional leadership in opposition to the president from getting much done, analysts are advising their clients.

Most analysts believe Democrats are also within striking distance of a Senate majority, though that outcome is significantly less likely than a House flip according to the polls.…